Priming mixture



rav s e patented Sept. 29, 1931 PATENT OFFICE JOSEPH D. MCNUTT, OF NEWHAVEN, CONNECTICUT, ASSIGNOR TO WINCHESTER RE- PEATING ARMS COMPANY, OFNEW HAVEN, CONNECTICUT, A CORPORATION OF DELAWARE PRIMING MIXTURE L'NoDrawing.

This invention relates to priming mixtures for small arms ammunition andmore particularly to non-corrosive priming mixtures. This application isa continuation in part of my copending application Serial No. 347,190,

filed March 14, 1929.

Heretofore rim fire priming mixtures have contained ground glass orother inert abrasive material to give the mixture sulficient harshnessto permit it to properly function. Antimony sulphide, one of thecommonly used fuels, also possesses a certain degree of abrasion, but noone heretofore has produced an operative priming mixture for rim firecartridges without ground glass or other inert abrasive material, eventhough,

antimony sulphide were used as the fuel.

Various carbonates, and other basic compounds, both organic andinorganic, have also been added to priming mixtures as stabilizingagents. Among such compounds I have employed barium carbonate. Bariumcarbonate, and other carbonates, have heretofore been used in the formof impalpable powder and have performed no other function except that ofa stabilizing agent.

I have found that Witherite, a natural occurring barium carbonate, maybe employed as a stabilizing agent in priming mixtures in place of theartificially produced barium carbonate, and when it is so used withantimony sulphide an operative rim fire mixture may be produced withoutthe use of ground glass or other inert abrasive material.

I have also found that witherite may be used to good advantage in placeof artificially produced barium carbonate in priming mix tures forcenter fire cartridges.

A suitable mixture for rim fire use may be formed by mixing theingredients of the following proportions:

The proportions of these ingredients may, of course, be varied,depending upon the commercial strength of the lngredients and toApplication filed October 28, 1930. Serial No. 491,812.

meet the requirements of various uses of the priming mixture.

As stated above, an important feature of the present invention is theuse of witherite to function both as a stabilizing agent and as anabrasive. Witherite is a mineral which is macro-crystalline and can thusbe ground to any desired degree of granulation. When used in conjunctionwith antimony sulphide, which also functions to some extent as anabrasive, the use of ground glass in a rim fire mixture may beeliminated. As indicated above, the fuel employed may consist partly ofantimony sulphide and partly of lead sulphocyanate. As is well known bythose skilled in the art, lead sulphocyanate produces a greater amountof heat in a shorter space of time thanantimony sulphide and its use asa portion of the fuel facilitates combustion of the priming mixture upondetonation. Except for the presence of some antimony sulphide, withinthe minimum limits expressed, for the purpose of producing the necessaryharshness in the priming mixture, I consider the use of these two fuelsas the mere substitution of equivalents Within the skill of anyexplosives chemist.

In mixing the ingredients I first Weigh out the oxidizing agent, fuelsand Witherite and mix them dry on paper. A small amount of a gumsolution, preferably 1 percent, such as is generally used in wetmixtures, is then added and worked in briefly by hand. The Wet fulminateof mercury, containing approximately 16 percent of Water, is thenWeighed out and added to the other ingredients and the whole mixed untila homogeneous mixture is obtained.

The mixture is then formed into individual pellets of the proper sizefor individual charges in the customary manner by means of a chargeplate provided with perforations adapted to mold pellets of the propersize'and weight. These pellets are then transferred to empty rim firecartridge shells in the usual way and forced to distribute themselves inthe hollow rims by spinning each shell in the customary rim fire loadingmachine. The shells, after the priming mixture has dried, may then beloaded with powder and bullets in the customary way.

As stated above, the mineral characteristics of witherite permit theground glass or other inert abrasive to be dispensed with and thenecessary harshness for rim fire mixture obtained when the witherite isused in c011- junction with antimony sulphide as a part of the fuel.lVhile it functions as an abrasive at the time of the burning of thepri1ning mixture, it does not have the destructive abrasive effect onthe bore of the firearm in which it is used that ground glass or otherinert abrasive materials have. lVhile I am unable to distinctly statewhy the witherite may be present to function as an abrasive and stillnot produce the effect referred to above on the bore of the firearm, itmay be stated that the witherite is probably converted into impalpablebarium oxide at the temperature of the explosion, after it has performedits function as an abrasive.

For a center fire priming mixture, I may employ the followingingredients in substantially the following proportions:

Witherite 2%-5% (preferably 3.: Barium carbonate, less than 1% Informing the center fire mixture the ingredients are first mixed and themixture then formed into individual )ellets of the proper size forindividual charges in the customary manner by means of a charge plateprovided with perforations adapted to mold pellets of the proper sizeand weight. These pellets are then transferred into primer cups of theproper size and the charged primer cups submitted to pressure in theusual manner and then loaded into empty shells. The shells, after thepriming mixture has dried, may then be loaded with powder in thecustomary way.

lVhile I have specifically disclosed the use of basic lead nitrate andbarium nitrate as oxidizing agents, other oxidizing agents may besubstituted therefor. I prefer to employ an oxidizing agent having anon-corrosive residue and as an example of a material that may besubstituted for the basic lead nitrate of the rim fire priming mixturedisclosed above,

Mercury fuhninate 30 -4070 (preferably 35.5%) Barium nitrate 40%50%(preferably 4'. 7,.) Lead sulphocyanate 14%1D% (preferably 16 "a(preferably .5

I may mention the well known oxidizing agent, barium nitrate. hen bariumnitrate is substituted for basic lead nitrate, certain changes in theproportions of the ingredients may be necessary to obtain the propersensitiveness and priming capacity, but these details of proportion andthe like are within the skill of the explosives chemist and specificexamples thereof are therefore not included in this specification.

I claim:

1. A priming mixture comprising mercury fulminate, an oxidizing agenthaving a noncorrosive residue, a fuel and witherite.

2. A priming mixture comprising mercury fulminate, an oxidizing agenthaving a noncorrosive residue, antimony sulphide and witherite.

3. A priming mixture comprising mercury fulminate, an oxidizing agenthaving a noncorrosive residue, lead sulphocyanate and witherite.

l. A priming mixture comprising mercury fulminate, an oxidizing agenthaving a noncorrosive residue, antimony sulphide, lead sulphocyanate andwitherite.

5. A priming mixture comprising mercury fulminate, basic lead nitrate,antimony sulphide and witherite.

6. A priming mixture comprising mercury fulminate, basic lead nitrate,antimony sulphide, lead sulphocyanate and witherite.

7. A priming mixture comprising 35 to 50% mercury fulminate, 23 to 33%basic lead nitrate, 5 to 15% lead sulphocyanate, 5 to 20% antimonysulphide, and 5 to 10% witherite.

8. A priming mixture comprising substantially 42.5% mercury fulminatecontaining approximately 16% of water, substantially 28% basic leadnitrate, substantially 10% lead sulphocyanate, substantially 12%antimony sulphide, and substantially 7.5% witherite.

9. A priming mixture comprising mercury fulminate, barium nitrate, leadsulphocyanate and witherite.

10. A priming mixture comprising substantially 35 to 50% mercuryfulminate, l0 to 50% barium nitrate, 14K to 19% lead sulphocyanate, and2 to 5% witherite.

11. A priming mixture comprising substantially 35.5% mercury fulminate,substantially 45% barium nitrate, substantially 16% lead sulphocyanateand substantially 3.5% wither- 1te.

12. A priming mixture comprising substantially 35.5% mercury fulminate,substantially 45% barium nitrate, substantially 16% lead sulphocyanate,substantially 8.5% witherite and substantially 5% barium carbonate.

In testimony whereof I aiiix my signature.

JOSEPH D. MoNUTT.

